Rotary pump devices are often used to assist the blood flow of patients. Typically, these devices are implanted in body of a patient and are supplied power by a separate power supply. Generally, one end of the device is attached to the heart of a patient (through a flexible cannula) while another end is attached to a vein or artery of the patient (also through a flexible cannula). When the pump receives power, it assists in the circulation of blood through the patient by transferring blood from one portion of the patient's body to another.
Prior to implantation of the devices, it is often desirable to visually confirm the operation of the device, despite the high levels of quality control that is implemented by device manufacturers to ensure device reliability. As such, users may attempt to connect the devices to their power supply. Thus, the devices are run at their predetermined operating speed “dry” (e.g., without any fluid moving through the device) which can result in accelerated wear of the device due to increased friction. To counteract this problem, some users may insert the device into a sterile fluid bath, but these sterile fluid baths can result in an increased risk of infection to a patient.
Furthermore, the devices often use sensorless speed control methodologies to maintain their speed independent of their load. In particular, reverse electromotive force methodologies (e.g., “back-EMF” methodologies) are often used to maintain the commutation of a brushless motor in the device at a predetermined operating speed. However, to test the devices, the user may not provide enough power for the devices to properly utilize back-EMF methodologies. For example, at a reduced voltage to reduce the speed at which the devices operate, there is often not enough back-EMF generated by the pump motor to maintain speed control, which may result in a pump motor stoppage (resulting in a false device failure diagnosis) or pump motor overspeed (resulting in possible device damage).
There is thus a need for an improved method of testing rotary pump devices for visual verification of their operation.